Item – Theses Canada

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OCLC number
922582622
Link(s) to full text
LAC copy
LAC copy
Author
Chung, Jennifer,
Title
Energy loss, a novel biomechanical parameter, correlates with aortic aneurysm size and histopathology
Degree
M. Sc. -- McGill University, 2015
Publisher
[Montreal] : McGill University Libraries, [2015]
Description
1 online resource
Notes
Thesis supervisor: Kevin J Lachapelle (Internal/Cosupervisor2).
Thesis supervisor: Richard L Leask (Internal/Supervisor).
Includes bibliographical references.
Abstract
"It is not well understood which ascending aortas will develop complications. Biomechanics may provide insights beyond the consideration of size alone, and improve risk prediction. Energy loss is a biomechanical parameter describing the relative amount of energy absorbed by the aorta during the cardiac cycle. We aim to correlate energy loss with ascending aortic aneurysm size and histopathology to elucidate the pathophysiology of aneurysm complications. Aneurysmal ascending aortic specimens were obtained during surgery. Controls were obtained from autopsy and organ donors. Biaxial tensile tests were performed on the four quadrants of the aortic ring. Energy loss was calculated using the integral of the stress-strain curve during loading and unloading. It was compared to size and the traditional biomechanical parameter, stiffness (apparent modulus of elasticity). Elastin, collagen and mucopolysaccharide content was quantified using Movat pentachrome staining of histology slides. Forty-one aortas were collected (34 aneurysmal, 7 control). Aneurysms exhibited increased stiffness (p<0.0001) and energy loss (p<0.0001) compared to control. Energy loss correlated significantly with aortic size (p<0.0001, r2=0.60). A hinge point was noted at a diameter of 5.5cm, after which energy loss rose rapidly. The relationship between energy loss and size became strongly linear once size was indexed to body surface area (p<0.0001, r2=0.78). Energy loss correlated with histopathology, especially the collagen to elastin ratio (p=0.0002, r2=0.49). High energy loss distinguished patients with pathological histology from others of similar diameters. As ascending aortas dilate, they exhibit greater energy loss, rapidly rising after 5.5cm. This mirrors the rise in complications at this size. Energy loss correlates with imbalances in elastin and collagen composition, suggesting a measurable link between histopathology and mechanical function."--
Other link(s)
digitool.Library.McGill.CA
digitool.library.mcgill.ca
escholarship.mcgill.ca
escholarship.mcgill.ca
Subject
Health Sciences - Medicine and Surgery